The father of a Southern California teenager who was killed by a man in the United States illegally took the stage at the Republican National Convention in Cleveland on behalf of Donald Trump.

Jamiel Shaw Jr. was killed near his Arlington Heights home in March of 2008 by Pedro Espinoza, an undocumented immigrant and known gang member.

On Monday, Jamiel Shaw Sr. addressed the thousands in attendance during the first evening of the RNC at the Quicken Loans Arena.

Before he took the stage, Jamiel Shaw Sr. spoke with ABC7's Elex Michaelson about his staunch support for the presumptive Republican presidential nominee.

"So powerful, but he has a heart. And to see that he has a heart, it made me gravitate toward him and I want to help him be president because I know he's going to do what he says he's going to do," Jamiel Shaw Sr. said.

Jamiel Shaw Jr., who was a star football player at Los Angeles High School, was shot and killed by Espinoza just one day after Espinoza was released from jail.

Prosecutors said Espinoza mistakenly perceived Jamiel Shaw Jr. as a rival gang member because he was carrying a red Spider-Man backpack.

"Illegal immigration is not a victimless crime," Jamiel Shaw Sr. said. "It needs to be dealt with. We need to secure the border, you know, we need to make America safe. We need to be able to live without being shot dead in the street."

Jamiel Shaw Sr. has spoken on behalf of Trump at previous events, but perhaps none as big as the national spotlight of the RNC.